(1. 中南大學(xué)化學(xué)化工學(xué)院，長沙 410083；
2. 中南大學(xué)粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 采用開路電位-時(shí)間曲線以及循環(huán)極化曲線研究了不同時(shí)效制度對Al-6.2Zn-2.3Mg-2.3Cu-0.16Zr-0.18Cr-0.3Yb合金(質(zhì)量分?jǐn)?shù)，%)在10 mmol/L NaCl+0.1mol/L Na2SO4溶液中的電化學(xué)腐蝕性能的影響。結(jié)果表明：不同時(shí)效耐局部腐蝕與應(yīng)力腐蝕的能力由強(qiáng)至弱的順序依次為T76+T6、T77、T76、T6。結(jié)合硬度和電導(dǎo)率測試發(fā)現(xiàn)，與常規(guī)T77相比，過時(shí)效再時(shí)效T76+T6處理的鋁合金同時(shí)具備更優(yōu)異的耐蝕和強(qiáng)度性能。并系統(tǒng)討論了點(diǎn)蝕電位(φpit)、自腐蝕電位(φcorr)、再鈍化電位(φrep)以及電位差值(φrep-φcorr，φpit-φcorr，φpit-φrep)作為腐蝕判據(jù)的可行性和局限性。
關(guān)鍵字: 鋁合金；熱處理；電化學(xué)腐蝕
（1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The effects of heat treatments on electrochemical corrosion behaviours of Al-6.2Zn-2.3Mg-2.3Cu-0.16Zr- 0.18Cr-0.3Yb alloy (mass fraction, %) in 10 mmol/L NaCl + 0.1mol/L Na2SO4 solution were investigated by open circuit potential and cyclic polarization curve. The results show that the localized corrosion and stress cracking corrosion resistance of various alloys with different ageing processes is in the following order: T76+T6>T77≈T76>T6. Together with the results of hardness and conductivity characterization, it can be found that, compared to those of the conventional T77 ageing, the novel three-step ageing T76+T6 shows the combination of better corrosion resistance and higher strength property. In addition, the suitability and limitations of using pitting potential (φpit), corrosion potential (φcorr), repassivation potential (φrep) and potential differences (φrep-φcorr, φpit-φcorr, φpit-φrep) as the corrosion criteria were discussed in detail.
Key words: Al-6.2Zn-2.3Mg-2.3Cu-0.16Zr-0.18Cr-0.3Yb alloy; heat treatment; electrochemical corrosion
